x/tools/gopls: fix folding range for function calls

[ShoshinNikita]

gopls version: gopls@e751756 (master branch)

Fold calls to sort.Slice and fmt.Println in VSCode (or, likely, any other editor with LineFoldingOnly set to true):

func _() {
	slice := []int{1, 2, 3}
	sort.Slice(slice, func(i, j int) bool {
		a, b := slice[i], slice[j]
		return a < b
	})

	sort.Slice(
		slice,
		func(i, j int) bool {
			return slice[i] < slice[j]
		},
	)

	fmt.Println(
		1, 2, 3,
		4,
	)
}

Not only the arguments but also the closing parentheses are being folded. There are several issues with this behavior:

1. Lack of the closing parenthesis makes code editing more difficult. For example, users have to unfold fmt.Println to add more code. This behavior is particularly frustrating when working with calls like t.Run.
2. It is inconsistent with the folding of function bodies and composite literals - } is always visible.

Current behavior	Expected behavior

[gabyhelp]

Related Issues

• x/tools/gopls: support folding a slice #38360 (closed)

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[gopherbot]

Change https://go.dev/cl/630056 mentions this issue: gopls/internal/golang: fix folding range for function calls